Grey metallic selenium photocells



March 14, 1961 R. D. GEORGEN ETAL 2,975,387

GREY METALLIC SELENIUM PHOTOCELLS Filed Oct. 28, 1955 IN V EN TORJ' BYTHOMAS E. (AA/DGIPEN United States Patent 2,975,387 GREY NIETALLICSELENIUM PHOTOCELLS Filed Oct. 28, 1955, Ser. No. 543,418

8 Claims. (Cl. 338-17) This invention relates to the manufacture andassembly of grey metallic selenium photocells, and more particularly toa group of said cells arranged in a mosaic pattern. While it hasheretofore been known to group individual selenium photocells into amosaic pattern comprising a plurality of such cells, it has also beencommon practice in such situations to treat each cell individually andto have each cell insulated from adjoining cells. It has also been knownto manufacture selenium rectifiers by making a number of rectifiers in asheet or mosaic pattern and subsequently separating the individualselenium rectifiers one from another by cutting or otherwise separatingthem.

The present invention is concerned primarily with the production of amosaic arrangement of selenium photocells comprising a plurality ofindividual areas, each of the areas being responsive to the applicationof light thereto. Such an arrangement of photocells has been foundhighly advantageous in reproducing a pattern of light and dark. In suchuse a picture or other pattern of light and dark areas is thrown on thesurface of the group of photocells and in accordance with the amount andlocation of the light in the pattern the individual portions of themosaic photocell will pass current or not thereby enabling signals to betransmitted in accordance with the light pattern.

The object of the invention is to simplify the construction as well asthe means and mode of operation of grey metallic selenium photocells,whereby such photocells may not only be economically manufactured, butwill be more efficient and satisfactory in use, adaptable to a widevariety of applications, and be unlikely to get out of repair.

A further object of the invention is to provide a photocell which may beeasily combined with others in adjacent contacting relation so as toprovide when so assembled a mosaic pattern or arrangement of photocellscovering a relatively large area.

A further object of the invention is to provide a mosaic arrangement ofselenium photocells in which there is no insulation or separationbetween the adjacent contacting photocells of the group.

A further object of the invention is to provide a mosaic pattern ofindividually effective selenium photocells in which the metallicselenium comprising the mosaic arrangement is homogeneous andconstitutes a single sheet of the material.

A further object of the invention is to provide a mosaic pattern ofselenium photocells in which there is a single common terminal andcircuit forming one side of the circuit for all individually effectivecells and an individual electrode or contact approximately centered ineach of the individually effective areas of the mosaic pattern.

A further object of the invention is to provide a selenium photocellpossessing the advantageous structural features, the inherentmeritorious characteristics and the mode of operation herein mentioned.

With the above primary and other incidental objects in view as will morefully appear in the specification,

the invention intended to be protected by Letters Patent.

consists of the features of construction, the parts and 2,975,387Patented Mar. 14, 1961 combinations thereof, and the mode of operationas hereinafter described or illustrated in the accompanying drawings, ortheir equivalents.

Referring to the accompanying drawing, wherein is shown one butobviously not necessarily the only form of embodiment of the invention:

Fig. 1 is a sectional view taken on line 1-1 of Fig. 2, showing one formof an individual cell which may be used to provide a mosaic pattern orgrouping of photocells;

Fig. 2 is a vertical sectional view taken on line 2-2 of Fig. 1;

Fig. 3 is a transverse sectional view taken on line 33 of Fig. 4 showinganother form of individual selenium photocells embodying the sameprinciples which may be advantageously arranged in a mosaic pattern;

Fig. 4 is a vertical sectional view taken on line 44 of Fig. 3;

Fig. 5 is a vertical sectional view taken on line 55 of Fig. 6 showinganother form and manner of produc ing a mosaic pattern of individuallyeffective selenium photocells; and

Fig. 6 is a horizontal sectional view of a mosaic arrangement ofindividually effective selenium photocells taken on line 66 of Fig. 5.

Like parts are indicated by similar characters of reference throughoutthe several views.

Referring to the drawings, in accordance with the illustrated form ofthe invention shown in Figs. 1 and 2, a selenium photocell comprises asolid block 10 of an appropriate selenium material, cast or otherwisemolded to the configuration shown. As a part of the molding operation,or subsequent thereto, there is imbedded in the block 10 a pair of metalpins or electrodes 11 and 12 longitudinally disposed in the block andsep arated from one another by the material thereof. At their one ends,the electrodes 11 and 12 extend through and beyond the block 10 and suchprojecting ends, it will be understood, are connected in series relationin an electrical circuit. The electrical resistance, as will be furtherunderstood, of the block 10 varies with intensity of applied light sothat a circuit may alternative- 1y be opened and closed between theelectrodes 11 and 12, as greater and lesser amounts of light are castupon the block 10.

In the case of the embodiment of Figs. 3 and 4, a block 13 is formedwhich is like the block 10 of the first embodiment but which has only asingle electrode 14 therein, the latter of which is centrally disposedwith respect to the margin of the block. Such margins are coated with alayer 15 of a metallic, for example silver, paint. The layer 15 is thuselectrically conductive and so may serve as one terminal of thephotocell while the electrode 14 serves as the other.

A mosaic arrangement of photocells may be achieved by bringing multiplecells as shown in Fig. 1 or 3 into side by side relation in a group.According to the further concept of a mosaic arrangement, however, theselenium block material is formed in a single piece thus providing forsimplicity of construction and fabrication as well as obtaining ahomogeneous state in the selenium material for more constant andconsistent response as among the several photocells comprising themosaic arrangement.

Thus, as shown in Figs. 5 and 6, the selenium material is molded orotherwise shaped to the form of a sheet, for example to the square flatformation illustrated. Electrodes 17 are imbedded in the sheet 16,arranged in parallel rows, with the electrodes of each row being spacedequi-distant from one another and with the electrodes of adjacent rowsbeing spaced apart equi-distant from one another. At their one ends, theelectrodes 17 terminate at what may be considered to be the upper orsensitive surface 18 of the sheet. At their other ends, the electrodes17 project through and beyond the opposite or lower surface 19 of thesheet for the attachment of electrical wire conductors thereto. Thesensitive surface 18 is formed with a spaced apart series of grooves 21running in one direction in the surface 18 and with another series ofspaced apart grooves 22 running in the opposite direction in thesensitive surface, the result being to form a checker board pattern insuch surface. At the center of each geometric figure so defined, is anelectrode 17. On each margin of the figure, in surrounding relation tothe electrode, are portions of the grooves 21 and 22. Within each groove21 and 22 is a coating or layer 23 of a metallic paint or likeconductive material, as the material comprising the layer 15 of Figs. 3and 4. The grooves 21 and 22 intersect one another so that the metalliccoating 23 forms a continuous network over the surface 18 and serves asa common terminal for all of the photocells comprised in the mosaicarrangement, each photocell further having an individual terminal in theform of an electrode 17.

The selenium photocells as disclosed, it will be understood, may be usedas light sensitive control valves which are capable of passing more thanone milliampere of light current when energized by a light source. Thephotocells may be used in series with sensitive relays or in conjunctionwith various type electronic triggering circuits, and particularly inthe form of its mosaic arrangement may be used as an integral part of areproduction process or system according to which light is caused topass through the writings or drawings to be reproduced and cast on tothe mosaic bank of photocells. The pattern of light and dark thus thrownon the surface of the group of cells is transformed into electricalsignals transmitted by wire from the electrodes 17. The pattern of lightand dark thrown on the surface of the cells passes therethrough inaccordance with the amount and location of the light so that the signalstransmitted are in accordance with the light pattern.

Neither the indicated size nor configuration of the geometric figures inthe mosaic arrangement illustrated are critical to the performance ofthe device, and may be changed as may be appropriate or desired.

From the above description it will be apparent that there is thusprovided a device of the character described possessing the particularfeatures of advantage before enumerated as desirable, but whichobviously is susceptible of modification in its form, proportions,detail construction and arrangement of parts without departing from theprinciple involved or sacrificing any of its advantages.

While in order to comply with the statute the invention has beendescribed in language more or less specific as to structural features,it is to be understood that the invention is not limited to the specificfeatures shown, but that the means and construction herein disclosedcomprise but one of several modes of putting the invention into effect,and the invention is therefore claimed in any of its forms ormodifications within the legitimate and valid scope of the appendedclaims.

Having thus described our invention, we claim:

I. A selenium photocell comprising a one-piece solid block of seleniummaterial having opposed surfaces one of which is the light receivingsurface, and separated electrical contacts forming a unitary part ofsaid block, said electrical contacts comprising a metallic point appliedto the light receiving surface in a geometric pattern and metal postmeans embedded in the block in spaced relation with portions of thepattern and projecting through and beyond the other one of said opposedsurfaces.

2. A selenium photocell comprising a one-piece solid block of seleniummaterial having opposed surfaces one of which is the light receivingsurface, and separated electrical contacts forming a unitary part ofsaid block. said electrical contacts comprising intersecting stripes ofmetallic paint on the upper surface of the block defining a mosaicpattern of multiple blocks, and an electrode embedded in the center ofeach block so defined, said electrode extending through the bottomthereof.

3. A unitary mosaic arrangement of a plurality of photocells, includinga one-piece sheet of selenium material, an electrical conductoradhesively mounted on one exposed surface of said sheet and laid out todefine a pattern of multiple contiguous geometric figures, and anelectrode imbedded in said sheet in approximately the center of each ofsaid geometric figures and projecting through the opposite exposedsurface of the sheet.

4. A unitary mosaic arrangement of a plurality of photocells, includinga one-piece sheet of selenium material, a groove formation in onesurface of said sheet defining a pattern of contiguous geometricfigures, each representing an individual photocell, an electrodeimbedded in said sheet in approximately the center of each of saidfigures at right angles to said one surface, said electrodes serving asindividual terminals for said photocells, and electrically conductivemeans in said groove formation serving as a common terminal for saidphotocells.

5. An arrangement according to claim 4, characterized in that saidelectrically conductive means is a metallic paint.

6. A unitary mosaic arrangement of a plurality of photocells, includinga one-piece sheet of selenium material, a plurality of spaced apartelectrodes imbedded in said material, and electrically conductive meansarranged on one surface of said sheet to define a pattern of contiguousgeometric figures representing individual photocells, said electrodesbeing located substantially in the center of respective figures andserving as individual terminals for said photocells while saidelectrically conductive means serves as a common terminal.

7. A selenium photocell mosaic, including unitary seleniurn means havingin one surface thereof a pattern of contiguous geometrical figures, eachrepresenting an individual photocell, an electrode imbedded in saidselenium means in approximately the center of each of said geometricfigures at right angles to said one surface, said electrodes serving asindividual terminals for said photocells, and electrically conductivemeans installed in said one surface in superposed corresponding relationto said pattern and serving as a common terminal for said photocells.

8. A selenium photocell comprising a block of selenium material havingopposed surfaces one of which is the light receiving surface, andseparated electrical contacts forming a unitary part of said block, saidelectrical contacts comprising conductive means applied to the lightreceiving surface in a geometric pattern and metal post means embeddedin the block in spaced relation with portions of the pattern, said metalpost means projecting through and beyond the other of said opposedsurfaces.

References Cited in the file of this patent UNITED STATES PATENTS1,790,736 Wald Feb. 3, 1931 1,880,289 Sukumlyn Oct. 4, 1932 1,899,026Fessenden Feb. 28, 1933 1,935,650 McCreary Nov. 21, 1933 1,936,514Lengnick Nov. 21, 1933 2,480,113 Betzler Aug. 30, 1949 2,540,490 RittnerFeb. 6, 1951 2,609,429 Law Sept. 2, 1952 2,668,184 Taylor et a]. Feb. 2,1954 2,678,401 Iaegcr May 11, 1954 2,711,464 Anderson et al. June 21,1955 2,747,104 Jacobs May 22, 1956 2,789,193 Anderson Apr. 16, 1957UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.2,975,387 March 14 1961 Robert D. Georgen et alo Column 3, lin 67 for"point" read paint Signed iand sealed ihis 22nd day of January 1963,

(SEAL) muss:

ERNEST W. SWIDER DAVID L. LADD Attesting Officer Commissioner of PatentsPatent N08 2,975,387

Robert De Georgen et all,

It is hereby certified t ent requiring correction and corrected belowehat error appears in the above numbered patthat the-said Letters Patentshould read as Column 3, line 67, for "point" read paint Signed iandsealed this 22nd day of January 19630 (SEAL) Attest:

ERNEST W. SWIDER DAVID L. LADD Attesting @fficer Commissioner of PatentsMarch 14 1961 Patent No. 2,975,387 March 14, 1961 Robert D. Georgen et31.,

It is hereby certified that er ent requiring correction and thatcorrected below.

ror appears in the above numbered patthe said Letters Patent should readas Column 3, line 67, for "point" read paint Signed fland sealed this22nd day of January 1963,

(SEAL) Attest:

ERNEST w. SWIDER DAVID LADD Attesting Officer Commissioner of Patents

